In a display device, a method for forming a bezel pattern on a substrate has been used instead of using a separate bezel structure in order to achieve the weight reduction and thinning.
In the method for producing a display substrate in the related art, a photolithography method or a screen printing method is used in order to form a bezel pattern. But in the case of the photolithography method, there is a disadvantage in that the production costs for forming a pattern are expensive, and the process is complicated. In the case of the screen printing method, the thickness of a formed pattern due to high viscosity of a composition is increased to several tens of μm, and accordingly, a step difference occurs between a pattern formation part and a pattern non-formation part. Furthermore, for a bezel part having a white or gold color instead of a black color, a bezel part is formed by using a method for recoating the color several times in order to obtain an optical density at a proper level, and as the printing frequency of the bezel pattern is increased as described above, the step difference between the pattern formation part and the pattern non-formation part is further increased.
In particular, in the case of a touch panel display in which a bezel pattern is disposed on an internal side surface of a display device, there occurs a problem in that when a transparent conductive film is coated, the conductive film is discontinuously coated or short-circuited. Also, when an upper substrate, for example, a film having an adhesive force such as a polarizing plate, is attached to the surface on which the bezel pattern is formed, if the step difference and the taper angle between the bezel pattern forming portion and the non-forming portion are large, the fine bubbles may be generated, or the entire film may be peeled off, which may impair visual quality. The cause of the release may occur when the restoring force of the film deformed at the time of adhering is larger than the adhesive force between the film and the pattern forming portion or the adhesive force between the film and the pattern forming portion.
Therefore, there is a need to develop a method in which adhesion with a film is improved as compared with the conventional method of forming a bezel pattern.